Volume 87, Number 2, July 2009
Article Number 26007
Number of page(s) 4
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 18 August 2009
EPL, 87 (2009) 26007
DOI: 10.1209/0295-5075/87/26007

Structural modifications induced by electron irradiation in SiO2 glass: Local densification measurements

G. Buscarino, S. Agnello and F. M. Gelardi

Department of Physical and Astronomical Sciences, University of Palermo - Via Archirafi 36, I-90123 Palermo, Italy, EU

received 16 June 2009; accepted in final form 15 July 2009; published July 2009
published online 18 August 2009

We report a study on the structural modifications induced in amorphous silicon dioxide (a-SiO2) by electron irradiation in the dose range from 1.2$\cdot$103 to 5$\cdot$106 kGy. This study has been performed by investigating the properties of the 29Si hyperfine structure of the $E ^\prime _{\gamma}$ center by electron paramagnetic resonance (EPR) spectroscopy. Our data suggest that the structural modifications induced by irradiation take place through the nucleation of confined high-defective and densified regions statistically dispersed into the whole volume of the material. In addition, we have estimated that in the high dose limit (D$\geqslant$ 105 kGy) the degree of densification associated to the local (within the defective regions) polyamorphic transition follows a characteristic power law dependence on the dose given by $bD^{\nu}$, where b = (2.0$\pm$0.3)$\cdot$10-3, $\nu$ = 0.160$\pm$0.004 and D is the irradiation dose measured in kGy.

61.80.Fe - Electron and positron radiation effects.
61.43.Fs - Glasses.
61.72.J- - Point defects and defect clusters.

© EPLA 2009